20555215 has 16 divisors (see below), whose sum is σ = 26293248. Its totient is φ = 15390496.

The previous prime is 20555209. The next prime is 20555219. The reversal of 20555215 is 51255502.

It is a happy number.

It is not a de Polignac number, because 20555215 - 2¹⁷ = 20424143 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20555215.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20555219) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3504 + ... + 7306.

It is an arithmetic number, because the mean of its divisors is an integer number (1643328).

Almost surely, 2^20555215 is an apocalyptic number.

20555215 is a deficient number, since it is larger than the sum of its proper divisors (5738033).

20555215 is a wasteful number, since it uses less digits than its factorization.

20555215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3878.

The product of its (nonzero) digits is 2500, while the sum is 25.

The square root of 20555215 is about 4533.7859455426. The cubic root of 20555215 is about 273.9306793575.

The spelling of 20555215 in words is "twenty million, five hundred fifty-five thousand, two hundred fifteen".